JP3787969B2 - Servo writing method to magnetic disk media - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic disk device for recording and reproducing data while positioning a magnetic head based on servo information recorded on the disk. Used for The present invention relates to a servo writing method.
[0002]
[Prior art]
In the magnetic disk device, data is recorded and reproduced while positioning the magnetic head based on the servo information recorded on the disk. As a method of forming the servo information on the magnetic disk medium, the following two methods are mainly used. There is.
[0003]
(1) First method: Servo writing method using a servo writer
(2) Second method: Whole surface unevenness servo method
Here, although detailed description of each is omitted, the first method is a method usually used for writing servo information in a current hard disk drive (HDD) device, and the second method includes the following: There is an example. The second method is disclosed in JP-A-2-21816, JP-A-3-228219, JP-A-4-95218, JP-A-4-182927, Nikkei Electronics 1993 3.7.19 (no). 568), 169p-182p, etc.
[0004]
Three outlines of the main method of forming the uneven servo pattern in the case of the second method, that is, the entire uneven servo method will be described.
[0005]
(I) First pattern forming method
The procedure of the first pattern forming method will be described with reference to the flowchart shown in FIG.
[0006]
In FIG. 17, in step ST101, a master pattern of a positioning servo pattern to be formed on a magnetic disk medium is produced by a method of laser cutting of an optical disk.
[0007]
In step ST102, based on the master pattern formed in step ST101, injection molding (when using a plastic substrate) or glass 2P method (reference: Kloosterboer, JGand Lippits, GJM, "Photopolymerizable coatings for Laservision Video Discs," J. Radiat. Curing, 11 (1), pp.10-21, 1984.) etc., form an uneven pattern on the surface of the nonmagnetic substrate.
[0008]
In step ST103, a magnetic layer is formed on the nonmagnetic substrate on which the uneven pattern is formed in step ST102.
[0009]
In step ST104, the magnetic layer on the surface of the nonmagnetic substrate formed in step ST103 is DC magnetized.
[0010]
According to the first pattern forming method, a magnetized concave / convex servo pattern is formed as shown in FIG. FIG. 18 is a sectional view of the concave / convex servo pattern in the track running direction in the magnetic disk medium.
[0011]
(Ii) Second pattern formation method
The procedure of the second pattern forming method will be described with reference to the flowchart shown in FIG.
[0012]
In FIG. 19, in step ST111, a master pattern is produced in the same manner as in step ST101 of the first pattern forming method.
[0013]
In step ST112, a concavo-convex pattern is formed on the surface of the nonmagnetic substrate in the same manner as in step ST102 of the first pattern forming method.
[0014]
In step ST113, similarly to step ST103 of the first pattern forming method, a magnetic layer is formed on the nonmagnetic substrate on which the concavo-convex pattern is formed.
[0015]
In step ST114, a large magnetic field is applied to the magnetic layer on the surface of the nonmagnetic substrate formed in step ST113, and DC magnetization is performed including the magnetic layer in the recess of the nonmagnetic substrate.
[0016]
In step ST115, a small magnetic field opposite to that in step ST114 is applied to the surface of the nonmagnetic substrate that has been DC-magnetized including the magnetic layer in the recess of the nonmagnetic substrate in step ST114. Only the magnetic layer of the convex portion is DC magnetized in the direction opposite to the concave portion.
[0017]
According to the second pattern forming method, a magnetized concave / convex servo pattern is formed as shown in FIG. 18A, compared with the concave / convex servo pattern by the first pattern forming method. There is an advantage that a large output can be obtained. Although the detailed description of the second pattern forming method is omitted, FIG. This is the same as the method described in FIG.
[0018]
(Iii) Third pattern forming method
The procedure of the third pattern forming method will be described with reference to the flowchart shown in FIG.
[0019]
In FIG. 20, in step ST121, a master pattern is produced in the same manner as in step ST101 of the first pattern forming method.
[0020]
In step ST122, a magnetic layer is formed on the nonmagnetic substrate.
[0021]
In step ST123, based on the master pattern formed in step ST121, a part of the magnetic layer on the nonmagnetic substrate is selectively removed by a technique such as etching. The steps from step ST121 to step ST123 are disclosed and disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 2-218016.
[0022]
In step ST124, the magnetic layer remaining on the surface of the nonmagnetic substrate obtained by the steps up to step ST123 is DC magnetized.
[0023]
According to the third pattern forming method, a magnetized concave / convex servo pattern is formed as shown in FIG.
[0024]
[Problems to be solved by the invention]
However, each of the above-described first method (method of servo writing using a servo writer) and second method (entire uneven servo method) have the following problems.
[0025]
(1) In the case of the first method in which servo writing is performed using a servo writer
The first problem is that it is difficult to ensure accuracy because the arm on which the magnetic head of the disk drive is mounted is mechanically positioned from the outside and servo signals are written.
[0026]
The second problem is that a large-scale device is required and a considerable time is required for writing, which increases the manufacturing cost.
[0027]
As a third problem, in a case where a large amount of data such as image data is continuously recorded and reproduced, a spiral track format normally used in an optical disc is more suitable. In the case of the method 1, it is easy to write the servo pattern concentrically, but it is difficult to write it in a spiral shape.
[0028]
(2) In the case of the second method, which is the entire surface unevenness servo method
The problem with the second method is that the manufacturing cost can be reduced, but the surface of the disk is not flat, so it is difficult to lower the magnetic head and the recording density is limited. However, in the case of this second method, it is easy to form a servo pattern in a spiral shape because a molding technique for an optical disc can be used.
[0029]
Therefore, the present invention has been made in view of such a problem, and it is easy to ensure accuracy, does not require a large-scale device, can prevent an increase in manufacturing cost, and further writes a servo pattern in a spiral shape. It is an object of the present invention to provide a servo writing method to a magnetic disk medium that is easy to perform and can increase the recording density.
[0032]
[Means for Solving the Problems]
In the servo writing method to the magnetic disk medium of the present invention, a concave / convex pattern for head positioning is formed on at least one surface of the magnetic disk medium to generate servo information, and at the same time, the other flat surface according to the concave / convex pattern. In addition, while performing write positioning on each surface of one or a plurality of magnetic disk media whose both surfaces are flat, each of the other flat surface and one or a plurality of magnetic disk media using the servo information as a magnetization reversal pattern. The problem described above is solved by writing on the surface.
[0033]
In the servo writing method to the magnetic disk medium of the present invention, a concave / convex pattern for head positioning is formed on at least one surface of the magnetic disk medium, and servo information is generated. The other flat surface and one or more magnetic disk media with servo information as a magnetization reversal pattern while performing write positioning on each surface of one or more magnetic disk media with flat surfaces and both surfaces The problems described above are solved by writing on each surface.
[0034]
Furthermore, in the servo writing method to the magnetic disk medium of the present invention, a concave / convex pattern for head positioning is formed on at least one surface of the disk medium to generate servo information, and at the same time, both surfaces are flat according to the concave / convex pattern. The above-described problem is solved by writing servo information as a magnetization reversal pattern on each surface of the one or more magnetic disk media while performing write positioning on each surface of the one or more magnetic disk media. .
[0035]
In the servo writing method to each magnetic disk medium of the present invention described above, if the concave / convex pattern for head positioning is arranged along the spiral locus, As servo information The magnetization reversal pattern can be recorded along the spiral trajectory. In addition, when performing write positioning on the flat surface of the magnetic disk medium according to the read uneven pattern, the rotational speed of the magnetic disk medium is adjusted. All more than twice It is also possible to perform closed loop control in which the gain decreases at an integer multiple frequency.
[0038]
As described above, the first point of the present invention is that a magnetic disk medium having a head positioning concavo-convex pattern formed on only one surface is attached to a spindle motor, and servo writing is performed according to the concavo-convex pattern formed on one surface. Servo information is written as a magnetization reversal pattern on the other flat surface while performing track positioning of the arm assembly.
[0039]
The second point of the present invention is that a magnetic disk medium having a head positioning unevenness pattern formed on only one surface and one or more magnetic disk mediums having flat surfaces on both sides are the same. The other flat surface of the magnetic disk medium on which the concavo-convex pattern is formed and the one or more magnetic sheets are stacked while positioning the track of the arm assembly for servo writing according to the concavo-convex pattern formed on one surface. Servo information is written as a magnetization reversal pattern on the flat surface of the disk medium.
[0040]
Furthermore, the third point of the present invention is that a positioning reference disk having a head positioning uneven pattern formed on at least one surface and one or more magnetic disk media each having a flat surface on both sides are the same. The servo information is written as a magnetization reversal pattern on one or a plurality of magnetic disk media while being stacked on a spindle motor and performing track positioning of an arm assembly for servo writing in accordance with an uneven pattern on a positioning reference disk.
[0041]
That is, in the present invention, the concave / convex servo pattern for head positioning can be formed with high accuracy by using, for example, a molding technique for an optical disk, and therefore, while positioning the track of the arm assembly for servo writing according to the concave / convex pattern for head positioning, By writing the magnetization reversal pattern on the flat surface, servo information can be recorded with high accuracy.
[0042]
Further, the surface on which the servo information is written as the magnetization reversal pattern is a flat surface without unevenness, and is suitable for increasing the recording density by reducing the flying height of the head.
[0043]
Further, since the forming technique for the optical disk can be used for forming the concave / convex servo pattern for head positioning, it is also suitable for forming a positioning pattern when using a spiral track format.
[0044]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0045]
A servo writing procedure in the servo writing method to the magnetic disk medium according to the first embodiment of the present invention will be described with reference to the flowchart of FIG.
[0046]
In FIG. 1, in step ST1, the one-side surface (hereinafter referred to as the first b surface) of the magnetic disk medium 1 in FIG. The concave / convex servo pattern for positioning the head is formed only on the head). As the concave / convex servo pattern for head positioning formed on the first-b surface of the magnetic disk medium 1, the patterns as shown in FIGS. 18A, 18B and 18C are given as examples. Can do. FIG. 18 in this case shows a cross-sectional view in the track running direction of the uneven servo pattern formed only on the first surface b of the magnetic disk medium 1 of the present embodiment.
[0047]
On the other hand, in the magnetic disk medium 1 of the first embodiment, a concave / convex pattern is formed on the surface opposite to the first surface (hereinafter referred to as the first surface) on which the concave / convex servo pattern for head positioning is formed. The magnetic layer is formed on the first surface (flat surface).
[0048]
Here, for example, as shown in FIG. 3B, the areas 2bs on which the concave / convex servo pattern is formed on the first 1b surface are arranged in a substantially radial pattern alternately with the data areas 2bd, and the number thereof is several tens to Several hundred.
[0049]
For example, as shown in FIG. 4, the uneven servo pattern area 2bs is composed of a synchronization information area, a track address information area, and a fine position information area. The pattern formed in the track address information area represents a data track number (so-called track address), and the pattern formed in the fine position information area represents a fine signal indicating a detailed position in the track. The pattern formed in the synchronization information area is a clock mark for extracting a synchronization clock necessary for reproducing the track address and the fine signal. Although details of these signals are omitted, they are formed based on a format already disclosed in, for example, Japanese Patent Application Laid-Open No. 8-194904 by the present applicant. The relationship between the concave and convex portions in the concave / convex servo pattern region 2bs may be opposite to that shown in FIG. Further, the pitch of the uneven servo pattern may be different from the pitch of the data track. That is, for example, the pitch of the data tracks on the surface on which the uneven servo pattern is formed may be twice the pitch of the uneven servo pattern. In some cases, it is possible to form ROM data by forming data bits with unevenness in a part or all of the data area on the surface on which the uneven servo pattern for head positioning is formed.
[0050]
Next, in step ST2 of FIG. 1, the spindle of the apparatus for writing the servo information on the flat surface of the 1a surface of the magnetic disk medium 1 on which the concave / convex servo pattern for head positioning is formed only on the 1b surface. Attach to motor. At this time, when the magnetic disk medium 1 is used as a storage medium of the removable magnetic disk device, the magnetic disk medium 1 may be previously mounted in a dedicated cartridge and then attached to the spindle motor.
[0051]
As a device for writing servo information, a magnetic disk device that finally incorporates the magnetic disk medium 1 may be used, or a dedicated device for writing servo information may be used. In the magnetic disk device or a dedicated device for writing the servo information, as shown in FIG. 5, magnetic data is transferred to the first b surface of the magnetic disk medium 1 on which the concave / convex servo pattern for head positioning is formed. A magnetic head 3b for recording / reproducing and a magnetic head 3a for recording / reproducing magnetic data on the flat surface of the opposite 1a surface are attached to the same arm assembly 9, for example, a VCM (voice coil). The motor is driven and positioned simultaneously by the actuator 4. The magnetic head, arm assembly, and VCM actuator are collectively referred to as a head assembly 6. This magnetic disk medium 1 is attached to a spindle motor 5. Here, as the magnetic head 3a for the flat 1a surface, a head having a lower flying height than the magnetic head 3b for the 1b surface on which the uneven servo pattern is formed can be used. Can be combined such that a thin film inductive head and an MR (MagnetoResistive) inductive composite head are used for the magnetic head 3a.
[0052]
In step ST3 of FIG. 1, the magnetic head 3b and the magnetic head 3a are attached on the basis of position information obtained from a signal obtained by reproducing the magnetic signal from the concave / convex servo pattern on the 1b surface by the magnetic head 3b. The arm assembly 9 is positioned at a reference position (for example, a predetermined position on the outer circumference side of the disk), and in this state, servo information for positioning is written as a magnetization reversal pattern on the flat first surface 1a by the magnetic head 3a. At this time, one recording / reproducing amplifier may be used in a time-sharing manner for the magnetic head 3a and the magnetic head 3b, or a dedicated recording / reproducing amplifier may be provided for each of them and used in parallel.
[0053]
A cross-sectional view in the track running direction of the magnetization reversal servo pattern region 2as on the flat surface of the 1a surface after the servo information is written is as shown in FIG.
[0054]
In step ST4 of FIG. 1, the arm assembly 9 is moved from the previous position to the first position based on the position information obtained from the signal reproduced by the magnetic head 3b from the magnetic servo pattern on the first-b surface. Positioning is performed by shifting the pitch of the data track on the surface (flat surface) by ½, and in this state, servo information for positioning is written on the surface 1a as a magnetization reversal pattern by the magnetic head 3a.
[0055]
In step ST5 of FIG. 1, the operation of step ST4 is repeated for a predetermined number of tracks.
[0056]
As a result, for example, as shown in FIG. 3A, the magnetization reversal servo pattern area 2as formed as servo information on the first 1a surface alternates with the data area 2ad as in FIG. 3B. Are arranged radially, and the number thereof is several tens to several hundreds. In the example of FIG. 3, the magnetization reversal servo pattern areas 2as are arranged in a substantially radial pattern alternately with the data areas in the same manner as the 1b surface shown in FIG. 3B, and the number thereof is the uneven servo pattern area 2bs. Are the same, but they are not necessarily the same and may be different.
[0057]
The magnetization reversal servo pattern area 2as is composed of, for example, a synchronization information area, a track address information area, and a fine position information area, similarly to the configuration of the uneven servo pattern area 2bs. However, the time length of the magnetization reversal servo pattern region may be different from the uneven servo pattern region. For example, the time length of the magnetization reversal servo pattern region may be shorter than that of the concave / convex servo pattern region, or the number of patterns in the fine position information region may be increased after shortening the pattern time interval.
[0058]
Note that the pitch for writing the magnetization reversal servo pattern can easily be the same as the pitch of the uneven servo pattern. For example, the pitch for writing the magnetization reversal servo pattern is half the pitch of the uneven servo pattern, and the number of tracks on the flat surface Can be twice the surface on which the concave / convex servo pattern is formed.
[0059]
The above is the description of the servo writing method to the magnetic disk medium 1 in the first embodiment.
[0060]
In the first embodiment, a magnetic disk device incorporating a magnetic disk medium on which a servo pattern is written by the servo writing method (when the magnetic disk device is used as a writing device for a magnetization reversal servo pattern, A magnetic disk cartridge (servo pattern) that incorporates a magnetic disk medium on which a servo pattern is written, and a magnetic disk medium in which the servo pattern is written, after writing a magnetization reversal servo pattern using a dedicated servo writing device. Are included in the cartridge after writing, and the servo pattern is written in the method after being incorporated into the cartridge). Further, the magnetic disk device in the case where the magnetic disk device itself that finally incorporates the magnetic disk medium is used as the writing device of the magnetization reversal servo pattern to the magnetic disk medium is also included in the first embodiment.
[0061]
FIG. 7 shows a schematic configuration of a main part (servo write circuit) of the apparatus that realizes the servo write method to the magnetic disk medium according to the first embodiment of the present invention. 7 that are the same as those in FIG. 5 are given the same reference numerals, and detailed descriptions thereof are omitted.
[0062]
The head positioning concave / convex servo pattern formed on the surface 1b of the magnetic disk 1 is reproduced by the magnetic head 3b for reading the positioning signal and amplified by the reproducing amplifier 103. The reproduction signal amplified by the reproduction amplifier 103 is input to the position signal generation circuit 104 and the timing generation circuit 105.
[0063]
The timing generation circuit 105 generates a timing signal for extracting a position signal from the reproduction signal and a timing signal for servo writing, the former being the position signal generation circuit 104 and the latter being the recording timing of the servo writing control block 120. Input to the control circuit 107.
[0064]
The position signal generation circuit 104 generates position information from the amplified reproduction signal based on the timing signal input from the timing generation circuit 105.
[0065]
The target position generation circuit 109 of the servo write control block 120 generates a target position signal that is sequentially offset by, for example, ½ of the pitch of the data track for a predetermined number of tracks. The target position signal generated by the target position generation circuit 109 is input to the positioning control circuit 106.
[0066]
The positioning control circuit 106 sends a control signal for controlling the VCM actuator 4 to the VCM driver 102 based on the position information input from the position signal generation circuit 104, and the VCM driver 102 receives the positioning control circuit 106. The arm assembly 9 is positioned at the target position by driving the VCM actuator 4 on the basis of the control signal from. The positioning control circuit 106 sends a positioning completion signal to the recording timing control circuit 107 of the servo write control block 120 when the arm assembly 9 is set to the target position.
[0067]
On the other hand, servo information corresponding to the current target position for forming the magnetization reversal servo pattern on the surface 1a is generated by the servo pattern generation circuit 108 of the servo write control block 120, and the recording timing control is performed after the positioning is completed. The time is managed by the circuit 107, sent to the recording / reproducing amplifier 101, and written to the first surface of the magnetic disk 1 by the magnetic head 3a for writing the servo information. At this time, the recording / reproducing amplifier 101 is held in the recording mode.
[0068]
The servo write control block 120 is provided with a normal write pattern verification circuit 110. For example, when the servo signal writing including the magnetization reversal pattern in all tracks is completed, the recording / reproduction amplifier 101 is set in the reproduction mode. Based on the position information from the uneven servo pattern formed on the 1b surface of the magnetic disk 1, the arm assembly 9 is positioned sequentially and the written magnetization reversal servo pattern is reproduced by the magnetic head 3a for servo writing. Thus, an operation for verifying the write pattern (so-called verify operation) is performed.
[0069]
Next, a second embodiment of the present invention will be described.
[0070]
A servo writing procedure in the servo writing method to the magnetic disk medium according to the second embodiment of the present invention will be described below in the order of main steps with reference to the flowchart of FIG. In the first embodiment described above, while the track positioning of the servo writing arm assembly is performed according to the concave / convex servo pattern for positioning the head formed on the 1b surface of the magnetic disk medium 1, the other 1a surface is subjected to positioning. In the second embodiment, the servo positioning arm assembly track positioning is performed in accordance with the head positioning concave / convex servo pattern formed on the 1b surface of the magnetic disk medium. While performing, the servo information is magnetized not only on the flat surface of the first a surface of the magnetic disk medium on which the concave and convex servo pattern is formed, but also on each flat surface of one or more magnetic disk media in which both surfaces are flat. It is written as a reverse pattern.
[0071]
In FIG. 8, in step ST11, as in step ST1 of the first embodiment, an optical disk laser cutting method, etc., similar to the case of the above-described full surface uneven servo system, etc. on the first b surface of the magnetic disk medium, etc. Thus, a concave / convex servo pattern for head positioning is formed. The first surface 1a opposite to the surface on which the concave / convex servo pattern is formed is a flat surface, and a magnetic layer is also formed on the flat surface.
[0072]
In step ST12 of FIG. 8, as shown in FIG. 9, the magnetic disk 11 on which the concave / convex servo pattern for head positioning is formed only on the 1b surface in step ST11, and one or a plurality of sheets having flat surfaces on both sides. A magnetic disk medium 18 is stacked on a spindle motor 15 of a device for writing servo information. In the example of FIG. 9, each surface of one or a plurality of magnetic disk media 18 whose both surfaces are flat surfaces is shown as a 2a surface, and the back surface is shown as a 2b surface. At this time, when each magnetic disk medium according to the present embodiment is used as a storage medium of a removable magnetic disk device, the magnetic disk 11 in which the concave / convex servo pattern for head positioning is formed only on the first surface b, and further both surfaces One or a plurality of magnetic disk media 18 each having a flat surface may be mounted on the spindle motor after being assembled in the cartridge 20 in the form shown in FIG. In the cartridge 20, the magnetic disks 11 and 18 are arranged in a case 32, and the center hole portion of the magnetic disks 11 and 18 is attached to the center core 31. The center core 31 is attached to the spindle motor.
[0073]
Here, as the apparatus for writing the servo information in the second embodiment, as in the case of the servo writing method to the magnetic disk medium in the first embodiment, finally, A magnetic disk device incorporating a magnetic disk medium may be used, or a dedicated device for writing servo information may be used. In the second embodiment, the magnetic disk device or the dedicated device for writing servo information, as shown in FIG. 9, has a magnetic surface on the first b surface of the magnetic disk 11 on which the concave / convex servo pattern for head positioning is formed. A magnetic head 13 for recording / reproducing data, and one or a plurality of magnets in which the first surface (flat surface) and both surfaces (second surface 2a and second surface 2b) on the opposite side of the magnetic disk 11 are flat surfaces. Each magnetic head 17 for recording / reproducing magnetic data on each flat surface of the disk medium 18 is attached to the same arm assembly 19 and is simultaneously driven and positioned by, for example, the VCM actuator 14. Hereinafter, the magnetic head, the arm assembly, and the VCM actuator are collectively referred to as a head assembly 16. Each magnetic head 17 can be a head having a flying height lower than that of the magnetic head 13. A combination of a thin film inductive head for the magnetic head 13 and an MR inductive composite head for each magnetic head 17 is also possible. Is possible.
[0074]
In step ST13 of FIG. 8, each magnetic head 17 is attached based on the positional information obtained from the signal reproduced by the magnetic head 13 from the concave / convex servo pattern on the first-b surface of the magnetic disk 11. The arm assembly 19 is positioned at a reference position (for example, a predetermined position on the outer peripheral side of each disk), and in this state, the first head surface (flat surface) and both surfaces (second surface 2a) on the opposite side of the magnetic disk 11 are moved by the magnetic heads 17. Servo information for positioning is written as a magnetization reversal pattern on each flat surface of one or a plurality of magnetic disk media 18 having a flat surface and a second surface b). At this time, the writing of the servo information as the magnetization reversal pattern by each magnetic head 17 may be performed all at once or in a time-sharing manner.
[0075]
In step ST14 of FIG. 8, the magnetic heads 13 and 17 are connected to each other based on the position information obtained from the signal reproduced from the magnetic head 13 by reproducing the magnetic signal from the concavo-convex servo pattern on the 1b surface of the magnetic disk 11. The attached arm assembly 19 is positioned by shifting from the previous position by, for example, 1/2 the pitch of the data track on each flat surface (the first a surface, the second a surface, and the second b surface). 17, servo information for positioning is written on each flat surface as a magnetization reversal pattern.
[0076]
In step ST15 of FIG. 8, the operation of step ST14 is repeated for a predetermined number of tracks.
[0077]
Thus, for example, as shown in FIG. 11A, the magnetization reversal servo pattern region 2as formed as servo information on the 1a surface of the magnetic disk 11, the 2a surface and the 2nd surface of each magnetic disk medium 18. The magnetization reversal servo pattern areas 3as and 3bs formed as servo information on the 2b surface are alternately arranged with the data areas 2ad, 3ad, and 3bd in a substantially radial manner, and the number thereof is several tens to several hundreds. The number of the magnetization reversal servo pattern areas 2as, 3as, 3bs may be the same as the number of the uneven servo pattern areas 2bs, as in the case of the servo writing method to the magnetic disk medium in the first embodiment. Although different, the example of FIG. 11 shows an example in which the number of the uneven servo pattern areas 2bs is twice the number of the magnetization reversal servo pattern areas 2as, 3as, and 3bs. When the number of the uneven servo pattern areas 2bs is increased as described above, there is an advantage that the positioning accuracy when writing the servo information as the magnetization reversal pattern can be improved. This advantage is the same when applied to the first embodiment.
[0078]
The above is the description of the servo writing method to the magnetic disk media 11 and 18 in the second embodiment.
[0079]
In the second embodiment, a magnetic disk device incorporating a magnetic disk medium on which a servo pattern is written by the servo writing method (when the magnetic disk device is used as a magnetization reversal servo pattern writing device; A magnetic disk cartridge (servo pattern) that incorporates a magnetic disk medium on which a servo pattern is written, and a magnetic disk medium in which the servo pattern is written, after writing a magnetization reversal servo pattern using a dedicated servo writing device. Are included in the cartridge after writing, and the servo pattern is written in the method after being incorporated into the cartridge). Furthermore, the magnetic disk device in the case where the magnetic disk device itself that finally incorporates the magnetic disk medium is used as the writing device of the magnetization reversal servo pattern to the magnetic disk medium is also included in the second embodiment.
[0080]
FIG. 12 shows a schematic configuration of a main part (servo writing circuit) of an apparatus that realizes the servo writing method to the magnetic disk medium according to the second embodiment of the present invention. 12 that are the same as those in FIGS. 7 and 9 are given the same reference numerals, and detailed descriptions thereof are omitted.
[0081]
The concave / convex servo pattern for head positioning formed on the 1b surface of the magnetic disk 11 is reproduced by the magnetic head 13 for reading positioning signals, amplified by the reproducing amplifier 103 as in FIG. 7, and amplified. The reproduced signal is input to the position signal generation circuit 104 and the timing generation circuit 105 as described above.
[0082]
The components after the position signal generation circuit 104 and the timing generation circuit 105 operate in the same manner as described above, and the VCM actuator 14 in FIG. 9 is driven by the VCM driver 132 based on the control signal from the positioning control circuit 109. As a result, the arm assembly 19 of FIG. 9 is positioned at the target position.
[0083]
On the other hand, the servo information corresponding to the current target position for forming the magnetization reversal servo pattern on the 1a surface of the magnetic disk 11 and the 2a surface and 2b surface of each magnetic disk medium 18 is servo write control. The servo pattern generation circuit 108 of the block 120 generates the signal and sends it to the recording / reproducing amplifier 131. The magnetic head 17 for writing the servo information uses the first a surface of the magnetic disk 11 and the second a surface of each magnetic disk medium 18. And written on the second surface b.
[0084]
Next, a third embodiment of the present invention will be described.
[0085]
A servo writing procedure in the servo writing method to the magnetic disk medium according to the third embodiment of the present invention will be described below in the order of main steps with reference to the flowchart of FIG. In the second embodiment described above, the servo information is written as the magnetization reversal pattern on the flat surface of the first reference surface 13a of the positioning reference disk 13 and the flat surfaces of the magnetic disk media 18. However, the third embodiment is different in that it does not include a disk medium on which an uneven servo pattern for head positioning is formed.
[0086]
In FIG. 13, in step ST21, as in the case of step ST1 of the first embodiment, laser cutting of the optical disk is performed on one side or both sides of the magnetic disk medium in the same manner as in the above-described full surface uneven servo system. An uneven servo pattern for head positioning is formed by a technique or the like. In the third embodiment, the magnetic disk medium on which the concave / convex servo pattern for head positioning is formed on one side or both sides is hereinafter referred to as a positioning reference disk, and the concave / convex servo of the positioning reference disk is also referred to. The one surface or both surfaces on which the pattern is formed are collectively referred to as a third surface.
[0087]
In the case of the third embodiment, the magnetic disk medium (positioning reference disk) for forming the concave / convex servo pattern for head positioning is used exclusively for head positioning for servo writing and used for data recording / reproduction. It is also possible to adopt a method that does not. In this case, the positioning reference disk does not need the data area as described above, and it is possible to form a concave / convex servo pattern over the entire disk surface. Thus, if the concave / convex servo pattern is formed over the entire surface of the disk, there is an advantage that the positioning accuracy in writing the magnetization reversal pattern can be increased.
[0088]
In step ST22 of FIG. 13, as shown in FIG. 14, the positioning reference disk 21 in which the concave / convex servo pattern for head positioning is formed on the third surface (one surface or both surfaces) in step ST21, and both surfaces are flat surfaces. One or a plurality of magnetic disk media 28 are stacked on a spindle motor 25 of an apparatus for writing servo information. In the example of FIG. 14, as in FIG. 9, each surface of one or a plurality of magnetic disk media 28 whose both surfaces are flat surfaces is shown as a 2a surface and the back surface is shown as a 2b surface. At this time, when each magnetic disk medium according to the present embodiment is used as a storage medium of a removable magnetic disk device, a positioning reference disk 21 having a concave / convex servo pattern for head positioning formed on the third surface, and further double-sided One or a plurality of magnetic disk media 28 each having a flat surface may be attached to the spindle motor after being assembled into the cartridge 20 in the form shown in FIG. 10, and the positioning reference disk 21 may be Alternatively, the magnetic disk medium 28 may be fixed to a spindle motor in advance, and only one or a plurality of magnetic disk media 28 having both flat surfaces may be assembled into the cartridge 20 and then stacked on the spindle motor. In the latter case, the positioning reference disk 21 is not used for data recording / reproduction.
[0089]
Here, the apparatus for writing the servo information in the third embodiment is the same as the case of the servo writing method to the magnetic disk medium in the first and second embodiments. Alternatively, a magnetic disk device incorporating the magnetic disk medium may be used, or a dedicated device for writing servo information may be used. In the third embodiment, in the magnetic disk device or the dedicated device for writing servo information, as shown in FIG. 14, the third surface of the positioning reference disk 21 on which an uneven servo pattern for head positioning is formed ( Each of a magnetic head (servo head) 23 for recording / reproducing magnetic data on one side or both sides, and one or a plurality of magnetic disk media 28 in which the both sides (the second a surface and the second b surface) are flat surfaces. Each magnetic head 27 for recording / reproducing magnetic data on a flat surface is attached to the same arm assembly 29 and is simultaneously driven and positioned by, for example, a VCM actuator 24. The magnetic head, arm assembly, and VCM actuator are collectively referred to as a head assembly 26. In the case of the third embodiment, the positioning reference disk 21 and each magnetic disk medium 28 can be made of different materials. For example, the positioning reference disk 21 is made of a resin or a glass substrate. A disk may be used, and each magnetic disk medium 28 may be a disk made of an aluminum substrate. Each magnetic head 27 can be a head having a lower flying height than the magnetic head (servo head) 23. The magnetic head 23 is a thin-film inductive head, and each magnetic head 27 is an MR inductive composite head. Combinations such as use are also possible.
[0090]
In the above description of the third embodiment, the disk medium (positioning reference disk) that forms the concave / convex servo pattern for head positioning is a magnetic disk medium. However, the positioning reference disk is a head for servo writing. When the data is used exclusively for positioning and not used for data recording / reproduction, an optical disk medium is used for the positioning reference disk, and the magnetic head (servo head) 23 is replaced with an optical head to reproduce the uneven servo pattern. It is also possible to perform. However, in the example of the third embodiment, in order to simplify the description, an example is given in which the positioning reference disk is a magnetic disk medium and the servo head is also a magnetic head.
[0091]
In step ST23 of FIG. 13, each magnetic head is based on position information obtained from a signal reproduced by the magnetic head (servo head) 23 from a magnetic signal from the concave / convex servo pattern on the third surface of the positioning reference disk 21. 27 is positioned at a reference position (for example, a predetermined position on the outer peripheral side of each disk), and in this state, the magnetic heads 27 cause the both surfaces (the second a surface and the second b surface) to be flat from the flat surface. Servo information for positioning is written as a magnetization reversal pattern on each flat surface of one or a plurality of magnetic disk media 28. At this time, the writing of the servo information as the magnetization reversal pattern by each magnetic head 27 may be performed all at once or in a time-sharing manner.
[0092]
In step ST24 of FIG. 13, the servo head 23 is based on position information generated by the magnetic head (servo head) 23 reproducing a magnetic signal from the concave / convex servo pattern on the third surface of the positioning reference disk 21. And the arm assembly 29 to which the magnetic heads 27 are mounted are shifted from the previous position by, for example, ½ the pitch of the data track on each flat surface (the 2a surface and the 2b surface), and in this state Each magnetic head 27 writes servo information for positioning as a magnetization reversal pattern on each flat surface.
[0093]
In step ST25 of FIG. 13, the operation of step ST24 is repeated for a predetermined number of tracks.
[0094]
The above is the description of the servo writing method to each magnetic disk medium 28 in the third embodiment.
[0095]
In the third embodiment, the magnetic disk device when the magnetic disk device itself that finally incorporates the magnetic disk medium is used as a device for writing a magnetization reversal servo pattern to the magnetic disk medium, and the head positioning. Servo writing when a magnetic disk medium that forms a concave / convex pattern for use is dedicated to head positioning for servo writing and not used for data recording / reproduction, and a dedicated device is used for writing servo information Each of which includes a device. Furthermore, for servo write applications of magnetic disk media for removable magnetic disk drives, this device is configured as a servo write dedicated drive in which a magnetic disk medium with a concave / convex servo pattern for head positioning is fixed to a spindle motor. If it is possible to attach and detach the disk medium on which servo information is to be written by inserting and removing the cartridge, it is considered that mass production is good and particularly effective.
[0096]
FIG. 15 shows a schematic configuration of a main part (servo writing circuit) of an apparatus for realizing a servo writing method to a magnetic disk medium according to the third embodiment of the present invention. 15 that are the same as those in FIGS. 7 and 14 are assigned the same reference numerals, and detailed descriptions thereof are omitted.
[0097]
The concave / convex servo pattern for head positioning formed on the third surface of the positioning reference disk 21 is reproduced by the magnetic head 23 (or optical head) for reading positioning signals, amplified by the reproduction amplifier 163, The amplified reproduction signal is input to the position signal generation circuit 104 and the timing generation circuit 105 as described above.
[0098]
The components after the position signal generation circuit 104 and the timing generation circuit 105 operate in the same manner as described above, and the VCM actuator 24 in FIG. 14 is driven by the VCM driver 162 based on the control signal from the positioning control circuit 109. As a result, the arm assembly 29 shown in FIG. 14 is positioned at the target position.
[0099]
On the other hand, the servo information corresponding to the current target position for forming the magnetization reversal servo pattern on the 2a surface and the 2b surface of each magnetic disk medium 28 is the servo pattern generation circuit 108 of the servo write control block 120. Is sent to the recording / reproducing amplifier 161, and is written onto the second a surface and the second b surface of each magnetic disk medium 28 by the magnetic head 27 for writing the servo information.
[0100]
Next, a fourth embodiment of the present invention will be described.
[0101]
In the fourth embodiment, the concave / convex servo pattern for head positioning as described in the first to third embodiments is arranged and formed on the disk along a spiral locus. As described above, even when the concave / convex servo pattern is arranged on the disk along the spiral locus, the same method of laser cutting of the optical disk as in the case of the entire concave / convex servo system can be used.
[0102]
As in the fourth embodiment, the concave / convex servo pattern for head positioning is formed on the disk along the spiral locus so that the servo information to be written on the flat surface is also along the spiral locus. Therefore, it is possible to easily realize a spiral track format suitable for use in recording and reproducing a large amount of data such as image data continuously.
[0103]
Next, a fifth embodiment of the present invention will be described.
[0104]
The fifth embodiment includes the steps ST3 and ST4 of the first embodiment, the steps ST13 and ST14 of the second embodiment, and the step ST23 of the third embodiment. In step ST24, when positioning the arm assembly (9, 19, 29) based on the position information obtained by reproducing the magnetic signal from the formed uneven servo pattern with the magnetic head, the spindle motor (5, 15 and 25), a closed-loop control system having a structure in which the gain decreases at a frequency that is an integral multiple of the number of rotations.
[0105]
FIGS. 16A and 16B show examples of a round transfer function of the head positioning control system in the fifth embodiment.
[0106]
In the head positioning control system having the characteristics shown in FIGS. 16A and 16B, a case is shown in which a filter with a gain reduction is inserted at a frequency that is twice to four times the rotational speed of the spindle motor. However, the present invention is not limited to this, and for example, a control system having a structure in which the gain decreases at a frequency of 2 to 8 times the rotational speed may be used. A control system having a decreasing structure may be used.
[0107]
In the head positioning control system having the characteristics shown in FIG. 16B, a filter having a peak in the rotational frequency of the spindle motor is also inserted, thereby reducing the positioning error due to the disk eccentricity. There is an effect to.
[0108]
When the head positioning control system of the fifth embodiment is used, an RRO (repeatable runout) component caused by a pattern forming error or the like of the uneven servo pattern is small because the gain at a frequency that is an integral multiple of the rotational speed of the spindle motor is small. Follow-up to (rotation-synchronized run-out component) is suppressed.
[0109]
Therefore, when the RRO component due to the pattern forming error or the like of the uneven servo pattern is relatively large, by using the head positioning control system of the fifth embodiment, transfer of servo information written as a magnetization reversal pattern on the flat surface Accuracy can be improved.
[0110]
As described above, according to each embodiment of the present invention, a concave / convex servo pattern for head positioning is formed on a disk in advance with high precision using a molding technique for an optical disk. Servo information is written as a magnetization reversal pattern on the flat surface or the flat surface of one or more other magnetic disk media.
[0111]
Therefore, it is not necessary to mechanically position the arm from the outside and perform servo signal writing unlike a normal servo writer, so that accurate servo information can be recorded and a small servo writing device or self-recording device can be used. Since servo writing can be performed by a single drive, the manufacturing cost can be reduced.
[0112]
Further, since the surface on which the servo information is written as the magnetization reversal pattern is a flat surface without unevenness, there is an effect that it is suitable for increasing the recording density by reducing the flying height of the head.
[0113]
Furthermore, there is also an effect that it is easy to form a positioning pattern in a spiral track format suitable for use in continuously recording and reproducing a large amount of data such as image data.
[0114]
【The invention's effect】
As described above, according to the present invention, a concave / convex pattern for head positioning is formed on a disk in advance with high accuracy using, for example, a molding technique for an optical disk, and another flat surface or another sheet or Servo information is written on a flat surface of a plurality of magnetic disk media as a magnetization reversal pattern. Therefore, like an ordinary servo writer, the arm is mechanically positioned from outside to write servo signals. Since there is no need, it is possible to record servo information with high accuracy and to perform servo writing with a small servo writing device or a single drive itself, thereby reducing the manufacturing cost.
[0115]
Further, the surface on which the servo information is written as the magnetization reversal pattern is a flat surface without unevenness, and is suitable for increasing the recording density by reducing the flying height of the head.
[0116]
Furthermore, it is possible to easily form a positioning pattern in a spiral track format suitable for applications in which a large amount of data such as image data is continuously recorded and reproduced.
[0117]
That is, in the present invention, it is easy to ensure accuracy, a large-scale device is not required, an increase in manufacturing cost can be prevented, and a servo pattern can be written in a spiral shape to increase the recording density. Is possible.
[Brief description of the drawings]
FIG. 1 is a flowchart illustrating a servo writing procedure in a servo writing method to a magnetic disk medium according to a first embodiment of this invention.
FIG. 2 is a perspective view of the magnetic disk medium according to the first embodiment in which a concave / convex servo pattern is formed on one surface (first surface b) and a magnetic layer is formed on the other flat surface (first surface a).
FIG. 3 is a diagram showing an arrangement of a data area and a magnetization reversal servo pattern area on the first surface and a data area and an uneven servo pattern area on the first surface of the magnetic disk of the first embodiment. .
FIG. 4 is a diagram showing a detailed configuration of an uneven servo pattern region.
FIG. 5 is a diagram showing a schematic configuration of main components around a magnetic head of the apparatus for writing servo information according to the first embodiment;
FIG. 6 is a cross-sectional view in the track running direction of a magnetization reversal servo pattern area on a flat disk surface after servo information is written.
FIG. 7 is a block circuit diagram showing a schematic configuration of a main part (servo write circuit) of the apparatus for realizing the servo write method to the magnetic disk medium according to the first embodiment of the present invention.
FIG. 8 is a flowchart showing a servo writing procedure in the servo writing method to the magnetic disk medium according to the second embodiment of the present invention;
FIG. 9 is a diagram showing a schematic configuration of main components around a magnetic head of an apparatus for writing servo information according to a second embodiment.
FIG. 10 is a diagram showing a schematic configuration of a disk cartridge when the magnetic disk medium according to the present invention is used as a storage medium of a removable magnetic disk device.
FIG. 11 shows the arrangement of the data area and the magnetization reversal servo pattern area on the first surface of the positioning reference disk of the second embodiment, the arrangement of the data area and the uneven servo pattern area on the first surface, and another magnetic disk. It is a figure which shows arrangement | positioning of the data area | region and magnetization reversal servo pattern area | region on each flat surface of a medium.
FIG. 12 is a block circuit diagram showing a schematic configuration of a main part (servo write circuit) of an apparatus for realizing a servo write method to a magnetic disk medium according to a second embodiment of the present invention.
FIG. 13 is a flowchart showing a servo writing procedure in the servo writing method to the magnetic disk medium according to the third embodiment of the present invention;
FIG. 14 is a diagram showing a schematic configuration of main components around a magnetic head of an apparatus for writing servo information according to a third embodiment.
FIG. 15 is a block circuit diagram showing a schematic configuration of a main part (servo write circuit) of an apparatus for realizing a servo write method to a magnetic disk medium according to a third embodiment of the present invention.
FIG. 16 is a diagram showing an example of a round transfer function of a head positioning control system in the fifth embodiment.
FIG. 17 is a flowchart showing a procedure of a first pattern forming method of an entire surface uneven servo system.
FIG. 18 is a cross-sectional view in the track running direction of a pattern formed by the whole surface uneven servo system.
FIG. 19 is a flowchart showing a procedure of a second pattern forming method of the whole surface uneven servo system.
FIG. 20 is a flowchart showing a procedure of a second pattern forming method of the whole surface uneven servo system.
[Explanation of symbols]
1, 11, 18, 21, 28 Magnetic disk, 3a, 3b, 13, 17, 23, 27 Magnetic head, 4, 14, 24 VCM actuator, 5, 15, 25 Spindle motor, 6, 16, 26 Head assembly, 9, 19, 29 Arm assembly, 31 Center core, 32 Case, 101, 131, 161 Recording / reproducing amplifier, 102, 132, 162 VCM driver, 103, 163 Reproducing amplifier, 104 Position signal generating circuit, 105 Timing generating circuit, 106 Positioning control circuit, 107 Recording timing control circuit, 108 Servo pattern generation circuit, 109 Target position generation circuit, 110 Write pattern verification circuit, 120 Servo write control block

Claims (6)

A concave / convex pattern for head positioning is formed on one surface of the magnetic disk medium, and write positioning is performed on the other flat surface of the magnetic disk medium in accordance with the concave / convex pattern read from the one surface of the magnetic disk medium. However, in the servo writing method to the magnetic disk medium to write the servo information as the magnetization reversal pattern on the other flat surface ,
When performing write positioning on the other flat surface of the magnetic disk medium according to the concavo-convex pattern read from the one surface of the magnetic disk medium, all integer multiples of at least twice the rotational speed of the magnetic disk medium A method of servo writing on a magnetic disk medium, characterized in that closed loop control is performed in which the gain decreases at a certain frequency . The concave / convex pattern for positioning the head of the magnetic disk medium is arranged along a spiral locus, and a magnetization reversal pattern as the servo information is formed on the other flat surface of the magnetic disk medium along the spiral locus. 2. The method of servo writing on a magnetic disk medium according to claim 1 , wherein the recording is performed in a form. An uneven pattern for head positioning is formed on one surface of the magnetic disk medium, and the other flat surface and both surfaces of the magnetic disk medium are flat according to the uneven pattern read from one surface of the magnetic disk medium. Alternatively, while performing write positioning on each surface of a plurality of magnetic disk media, the servo information is used as a magnetization reversal pattern and the other flat surface and both surfaces of the one or more magnetic disk media are flat. In the servo writing method to the magnetic disk medium to be written on each surface ,
When performing write positioning on each surface of one or a plurality of magnetic disk media having the other flat surface and both surfaces of the magnetic disk medium flat according to the concavo-convex pattern read from the one surface of the magnetic disk medium. A method of servo writing to a magnetic disk medium, wherein closed loop control is performed in which the gain decreases at all integer multiple frequencies equal to or greater than twice the rotational speed of each magnetic disk medium . The concave / convex pattern for positioning the head of the magnetic disk medium is arranged along a spiral trajectory, and the magnetization reversal pattern as the servo information is used as the other flat surface and both surfaces of the magnetic disk medium are flat. 4. A servo writing method to a magnetic disk medium according to claim 3 , wherein recording is performed on each surface of one or more magnetic disk media in a shape along the spiral locus. A concavo-convex pattern for head positioning is formed on at least one surface of the disk medium, and write positioning is performed on each surface of one or a plurality of magnetic disk media having flat surfaces according to the concavo-convex pattern read from the disk medium. In the servo writing method to the magnetic disk medium, the servo information is written as a magnetization reversal pattern on each surface of the one or more magnetic disk media whose both surfaces are flat .
Two times the rotational speed of each magnetic disk medium when performing write positioning on each surface of one or more magnetic disk media whose both surfaces are flat according to the uneven pattern read from the one surface of the disk medium A servo writing method to a magnetic disk medium, wherein closed-loop control is performed in which the gain decreases at all integer multiple frequencies . The concave / convex pattern for positioning the head of the disk medium is arranged along a spiral trajectory, and the magnetization reversal pattern as the servo information is formed on each surface of one or a plurality of magnetic disk media whose both surfaces are flat. 6. The method of servo writing on a magnetic disk medium according to claim 5 , wherein recording is performed in a shape along the spiral locus.

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